Ms sims is putting away 22 books. she can put them on the table in stacks of 10 or as single books. what are the different way ms sims can put away the books

If Ms Sims can either put the books on the table in stacks of 10 or as single books.
If she decides to put them on the table in stacks of 10 (there are 2 group of 10 books and 2 single books), she can do that in the following ways:
1.  group1 of 10 books, group2 of 10 books, book1, book2
2.  group 2 of 10 books, group1 of 10 books, book1, book2
3.  group1 of 10 books, group2 of 10 books, book2, book1
4. group 2 of 10 books, group1 of 10 books, book2, book1

which are 4 ways.
If she decides to put the books as single books there are: 
n!/r!(n-r)! = 22!/1!(22-1)!=22!/21!=22*21!/21!=22 ways

So , there are 4 ways + 22 ways= 26 possible ways for Ms Sims to arrange the  books on the table. 

Do the inverse operation